The present invention relates to fluid conveying apparatus in general, and more particularly to improvements in assemblies wherein a pump driven by an electric motor, conveys a liquid, especially a liquid fuel.
The copending application of Nusser et al. discloses a fuel pump assembly wherein the pump and the electric motor are installed in a common housing and the rotors of the pump and electric motor rotate about a fixed shaft. The rotor of the pump is integral with an element of the rotor of the electric motor. It is further known to provide a discrete coupling which transmits torque from the rotor of the electric motor to the pump rotor. The wear on such couplings is extensive so that the radial and/or tangential play of the rotary parts increases beyond a permissible value after a relatively short period of use of the pump assembly. It has been observed that the pump assembly which embodies such a coupling is likely to become inoperative at the most inopportune time and that the generation of noise increases disproportionately as the wear upon the coupling progresses.